1. Field of the Invention
The present invention relates to the field of electrosurgery. In particular, the present invention relates to suction sleeves for electrosurgical devices for the evacuation of hot gasses, bodily fluids and other aspirates from an electrosurgical site.
2. Description of the Related Information
In use, electrosurgical instruments generate a great deal of heat at and around the RF cutting element of the instrument. All of the RF energy applied to the device is typically concentrated at the distal cutting element of the device, which consequently experiences a high current density. This high current density creates an arc between the targeted tissue and the cutting element of the device, which arc cuts the targeted tissue by vaporization of the cells that come into contact with the arc. This arc also creates very high temperatures. As the cells are vaporized, hot gasses (such as steam and smoke, for example) are created. Moreover, when arterial blood or other fluids fill the cavity around the cutting element of the electrosurgical element, these fluids are rapidly heated.
The presence of such hot gasses has several adverse consequences. First among these adverse consequences is thermal damage to the otherwise viable and healthy tissue surrounding the electrosurgical site. Second, the presence of heated fluids may also adversely affect the operation of the RF device itself. As the fluids come into contact with the RF cutting element of the electrosurgical device, the arc generated within the gap between the targeted tissue and the distal RF tip of the device may be lost. In turn, this loss of arc results in a decrease in the current density at the cutting element of the device, which current is then redistributed over the comparatively greater surface area of the distal region of the RF device. Indeed, instead of the RF energy being concentrated in the very small area of the cutting element (e.g., cutting blade or tip) of the device (which leaves adjacent areas relatively unaffected by the great temperatures generated at the arc), the applied RF energy is spread out over the greater surface of the distal region of the RF device, thereby heating the entire cavity. This heating, in addition to causing unintended thermal damage to adjacent tissue and structures, may also damage the biopsy specimen, destroying the architecture of the severed tissue and hampering histopathological examination thereof. Moreover, the heat generated at the cutting element of the device may also transfer to the shaft of the device, even during a procedure of relatively short duration.
To reduce the unintended thermal damage to adjacent tissues, it is necessary to evacuate the hot gasses and fluids from the electrosurgical site. Doing so in an efficient manner reduces the internal temperature of the cavity within which the RF procedure is being carried out, and reduces thermal damage to adjacent tissues. Moreover, efficient evacuation of gasses, fluids and smoke facilitates the re-initiation of the RF arc by re-creating the gap between the targeted tissue and the RF tip.
From the foregoing, it is apparent that evacuation of hot gasses and fluids is essential to prevent unintended thermal damage to adjacent tissue structures and to insure the maintenance of the RF arc at the distal tip of the electrosurgical device. What are needed, therefore, are devices for evacuation of heated gasses and fluids from an RF electrosurgery site. Such devices should efficiently remove both heated gasses and fluids without, however, unduly increasing the size of the device near the distal tip of the device. Such a device, moreover, should not hamper the physician as he or she manipulates (e.g., rotates) the electrosurgical device during the procedure. Ideally, such device should also be configured such that tissue coming into contact with it does not block the evacuation of the heated gasses and fluids.